Left his medical practice in South Africa to join identical twin brother, Thomas, in founding generic drug maker Hexal AG in 1986. Brothers eventually built Germany's second-largest generic drug maker. In February 2005 sold business as well as their 68% stake of U.S. Eon Labs to Novartis for $7.5 billion. Now brothers run their Santo Holding investment arm, which invests in the German biotech sector, in particular companies involved in cancer research. Brothers have established a neuroscience research center in Frankfurt named after their father, Ernst Strungmann. Said to love sailing, golf and skiing.